House Republican leaders are poised to release Monday evening an expansive series of changes to their Obamacare repeal bill in a last-ditch attempt to win enough support to get the bill passed.

Requested by President Donald Trump, the amendment includes perks for restive conservatives who wanted optional work requirements and block granting in Medicaid, as well as a potential olive branch to wary centrists who demanded more help for older Americans to buy insurance, POLITICO has learned.

The amendment would establish a reserve fund of at least $75 billion for tax credits to help the core constituency that propelled Trump to the White House: Americans between 50 and 64, who would see their premiums skyrocket under the current repeal plan. But the amendment would not set up the tax credits – it would instruct the Senate to do so, forcing House Republicans to take a vote on something the upper chamber would do later.

The amendment is also expected to repeal Obamacare’s taxes a year earlier than originally planned, a win for conservatives who want to eliminate the Affordable Care Act as quickly a possible.

It’s still unclear whether the changes are enough to win over the 216 Republicans needed to pass the measure in a high-profile vote planned for Thursday. But GOP leadership insiders and White House officials firmly believe the changes will corral the necessary votes.

House Speaker Paul Ryan and his top lieutenants have been meeting with holdout moderates to find out what’s needed to secure their support, while White House budget director Mick Mulvaney, a former Freedom Caucus member, has been working the far-right. Trump on Tuesday is expected to come to Capitol Hill to rally one last time with the entire House Republican conference.

House Freedom Caucus Chairman Mark Meadows told reporters Monday evening that the negotiations are over and that the hard-line conservative coalition didn’t get what it wanted in the bill. He admitted that Republican leaders are successfully picking off his members a sign that the repeal bill may get enough support on the House floor on Thursday.

“They’re already whipping with a whip that’s 10 feet long and 5 feet wide,” Meadows told reporters, adding that the Freedom Caucus won’t take an official position against the bill.

He predicted the bill would fail unless further changes are made, but he backed off an earlier claim that there would be 40 no votes.

“In fact, I already know of people who have changed their mind,” he said.

Among other changes to the repeal bill, the amendment would deletea provision that would have allowed consumers to move leftover tax credit money into a Health Savings Account. Anti-abortion groups had raised concerns that the provision might be eliminated under the Senate’s strict budget rules and inadvertently allow for taxpayer funding of abortion.

The amendment would also change federal Medicaid reimbursement rates for the elderly and disabled, a win for governors who were concerned about cuts.

Two of the changes were essential to winning over the support of the Republican Study Committee. Trump met with leaders of the conservative group last week and agreed to allow work requirements in Medicaid as well as give states the option of converting their Medicaid programs into block grants. Both concessions were heralded by conservatives as necessary changes to the health entitlement and long-term wins. Some states sought work requirement approval under the Obama administration, but were rebuffed by federal officials.

The new tax credits could be important to winning over centrists. The boost is designed to counter the huge financial hit thatpeople between the ages of 50 and 64 were expected to face if their premiums are allowed to be substantially higher than younger people. The powerful interest group AARP mobilized its members to oppose the bill in part because of the potentially huge cut to Baby Boomers.

But it’s unclear whether a reserve fund earmarked for tax credits – one that the Senate will have to put together – will be sufficient to convince enough House Republicans to support the legislation. The chamber’s Democrats are expected to be united in opposing the repeal bill.

The Congressional Budget Office said last week that under repeal, health insurance premiums on average would jump 20 percent to 25 percent for a 64-year-old. That’s because insurers would be able to charge older people much more than they charge younger Americans.

A 64-year-old making $26,500 would have paid about $1,700 for an insurance policy under Obamacare. But under the repeal plan, that would jump to about $14,600, CBO said.

There is also a targeted change to Medicaid funding that’s specifically designed to garner support from New York’s delegation. It would attempt to transfer more Medicaid spending from counties to the state, by blocking New York from obtaining federal reimbursements for payments made by counties.

Rep. Chris Collins and other New York Republicans have been pushing leaders to add the amendment. Rep. Claudia Tenney told local reporters that the inclusion of the amendment would be essential to win her support for the whole repeal bill.

John Bresnahan, Rachana Pradhan and Paul Demko contributed to this report.